A titular see in Pisidia, suffragan of Antioch. Sagalassus was one of the chief towns of Pisidia, near the north-west boundary of that province, in a fertile plain surrounded by hills, situated on the banks of an affluent of the Cestrus, a river which is represented on its coins. Alexander stormed it, after defeating its inhabitants in the neighbourhood. Cneius Manlius ravaged the district and made it pay a heavy war indemnity. After being subject to Amyntas, Tetrarch of Lycaonia and Galatia it became part of the Roman province of Pisidia. nothing else is known of its history, though it is mentioned by most of the ancient geographers; it is to be noted that Strabo (XII, 569) places it less accurately in Isauria, and Ptolemy (V, iii, 6) locates it erroneously in Lycia. Until the thirteenth century the "Notitiæ episcopatuum" mention it as the first suffragan see of Antioch in Pisidia. Le Quien (Oriens christianus, I, 1041) mentions four of its bishops: Jovius, present at the Council of Constantinople, 381; Frontianus, at Chalcedon, 451; Theodosius, at Nicæa, 787; Leo, at Constantinople, 869. This formerly wealthy and fortified city is now a poor village, called Aghiassoun by the Turks, about twenty-three miles south of Isbarta, in the vilayet of Koniah, containing some hundred inhabitants. It has immense ruined monuments, all later than the second century A. D.: a theatre, vast portico, gymnasium, ramparts, tombs, sarcophagi, churches, etc.